This project draws on and advances our understanding of migration and inter-household transfers as risk-sharing and consumption-smoothing mechanisms in Mexican communities. It specifically examines rainfall variability as a source of exogenous environmental risk. Long-term interannual variability measures the risk associated with agriculture in a location, while short-term interannual variability reflects some natural random and cyclic variability and some increases in variability due to anthropogenic climate change. Thus, effects of long-term variability show the effects of environmental risk codified in social institutions that have evolved in a community while effects of short-term variability show active adaptation to environmental risk. Effects of single year deviations from the long-term average rainfall, in contrast, show immediate responses to income or production shocks. Thus, the project will distinguish between several possible mechanisms linking environmental risk to human behavior, contributing to the interdisciplinary literatures on household decision-making in developing countries and on human adaptation to changing climate. The project uses publicly available social survey data, the Mexican Family Life Survey (MxFLS), to measure migration, inter-household transfers, and key control variables. These data will then be merged with precipitation measures constructed from hourly rainfall data from approximately the last 35 years from 256 weather stations in Mexico. The two data sources will be merged using the municipio, the finest geography identified in the MxFLS data, with social survey data matched to the record from the weather station closest in Euclidean distance to the centroid of the municipio. Event history and logit regression models of permanent and temporary migration out of communities will examine the differing effects of long-term average interannual variability in rainfall, short-term interannual variability, and single year deviation from the long-term average rainfall. Logit regression models of inter-household transfers examine the effects of these same variables. PUBLIC HEALTH RELEVANCE: This project examines the ways in which climate variability influences human behavior, focusing on migration and resource-sharing within families. We analyze the relationships between changes in the amount of rainfall and the year-to-year variation in amount, and migration, and support of family members with money, time and goods, between 2001 and 2005 in communities across Mexico.